Shame. The feeling that "I am a mistake." That "I am bad." It leads to a deep sense of disconnect (triggering the PANIC circuit discussed in the post on affective neuroscience). Shame can be at the root of addictions, perfectionism, and a host of other sorrows and suffering. Brene Brown has studied shame, and her message is easily accessible. That millions of people have watched this TEDtalk on shame speaks the pervasiveness in our culture.
http://www.ted.com/talks/brene_brown_listening_to_shame
http://www.ted.com/talks/brene_brown_listening_to_shame